Which of the following $3 d -m e t a l$ ion will give the lowest enthalpy of hydration $(\Delta_{ hyd } H )$ when dissolved in water?
$Cr ^{2+}$
$Mn ^{2+}$
$Fe ^{2+}$
$Co ^{2+}$
$Zn$ and $Hg$ belong to the same group, they differ in many of their properties. The property that is shared by both is
Electrons in a paramagnetic compound are
Assertion : Cuprous ion $(Cu^+)$ has unpaired electrons while cupric ion $(Cu^{2+})$ does not.
Reason : Cuprous ion $(Cu^+)$ is colourless whereas cupric ion $(Cu^{2+})$ is blue in the aqueous solution.
$\mu = \sqrt{15}$ is true for the pair :-
When $KMnO_4$ solution is added to hot oxalic acid solution, the decolourisation is slow in the beginning but becomes instantaneous after some time. This is because